Bowl-type fixed vibratory polishing mills are well-known and widely used by hobbyists and machine shops. These machines are commonly known as "tumblers" and are used to polish gems, to de-burr small machine parts, and for other similar operations. Typically, in operation, parts are placed inside of the work chamber or bowl of the tumbler, which is also filled with a solid abrasive work media, such as ceramics, plastics, sand or steel shot. The vibrating action of the bowl circulates the parts through the work media to achieve the desired abrading or polishing.
To achieve the proper circulating action of the work media and parts, the sides of the work chamber are typically bowl-shaped and inwardly turned at the top. The bottom of the bowl may have a peak rising from the center. Typically, the bowl is rigidly affixed to an oscillating platform so that efficient oscillation can be transmitted to the bowl.
However, these conditions present a problem after the treatment process is completed, and the parts and media are to be removed from the bowl and separated. Most commonly, this is achieved by simply turning the machine upside down and dumping out the parts and work media, and picking the parts from the work media by hand. Before treating another group of parts, the work media is then reintroduced to the work chamber and the new parts to be treated are added.
The use of a vibratory mill thus requires substantial dumping and replacement of the work media which is often a messy and time-consuming effort. It is an object of the present invention to provide a fixed vibratory, bowl-type mill with means for conveniently separating parts from the work media after the treatment process has been completed. It is a further object of the present invention to provide a vibratory mill with means to remove treated parts from within the work chamber bowl without removing the work media. Other objects, advantages and uses of the present device will be readily apparent to those of ordinary skill in the art, given the following drawings and further description.
There have been several prior art patents directed to vibratory mills. U.S. Pat. No. 3,435,565 discloses a device for the surface treatment of work pieces. The work pieces are extracted after they have been treated by lowering a sieving basket into the circulating mask. The flow of the mask containing the work results in both the mask and the work being deposited in the basket. The basket can then be raised and the parts removed.
The system specifically includes a vertically rotating shaft to accomplish media removal. The vertical rotating shaft is secured at its bottom to a dished bowl which closes the lower end of the stationary vertical tub mounted on a base. The shaft extends upwardly and has a square shaft on its outside which can be clutched and declutched to the inner shaft as desired, in order to rotate the square shaft.
The perforated basket is secured to the lower end of the sleeve to receive the circulating mask and the work pieces. To remove the work pieces, the basket is connected by the clutch to rotate with the bottom of the bowl, and the cylinder is operated to lower the basket into or near the bowl. The basket is then mechanically lifted while rotating to discharge the mask and retain the work.
U.S. Pat. No. 3,774,888 to Isaacson discloses a system in which electromagnets are used to vibrate a container holding a mass and work pieces in an off-centered manner, so as to establish an orbital or circular flow up one side, across the top, and down the other side of the container. The device includes a scoop which may comprise either a curved or mesh or a tray-like mesh which includes levers which enable one to move the screen down into the orbital path and intercept the mass and work pieces, and to then lift the mesh upward where it can be shaken to return the mass to the container.